Phylogeny and evolution of the genus Cervus (Cervidae, Mammalia) as revealed by complete mitochondrial genomes

Abstract

AbstractMitochondrial DNA (mtDNA) lineages are recognized as important components of intra- and interspecific biodiversity, and allow to reveal colonization routes and phylogeographic structure of many taxa. Among these is the genusCervusthat is widely distributed across the Holarctic. We obtained sequences of complete mitochondrial genomes from 13Cervustaxa and included them in global phylogenetic analyses of 71 Cervinae mitogenomes. The well-resolved phylogenetic trees confirmedCervusto be monophyletic. Molecular dating based on several fossil calibration points revealed thatca. 2.6 Mya two main mitochondrial lineages ofCervusseparated in Central Asia, the Western (includingC. hangluandC. elaphus) and the Eastern (comprisingC. albirostris,C. canadensisandC. nippon). We also observed convergent changes in the composition of some mitochondrial genes inC. hangluof the Western lineage and representatives of the Eastern lineage. Several subspecies ofC. nipponandC. hangluhave accumulated a large portion of deleterious substitutions in their mitochondrial protein-coding genes, probably due to drift in the wake of decreasing population size. In contrast to previous studies, we found that the relic haplogroup B ofC. elaphuswas sister to all other red deer lineages and that the Middle-Eastern haplogroup E shared a common ancestor with the Balkan haplogroup C. Comparison of the mtDNA phylogenetic tree with a published nuclear genome tree may imply ancient introgressions of mtDNA between differentCervusspecies as well as from the common ancestor of South Asian deer,Rusa timorensisandR. unicolor, to theCervusclade.